Thermoelectric properties of interacting double quantum dots

TL;DR

This paper analyzes the thermoelectric behavior of interacting double quantum dots, providing analytical formulas and exploring efficiency, power, and thermal rectification in various configurations.

Contribution

It extends an analytical formalism to asymmetrically coupled double quantum dots and derives explicit expressions for thermoelectric quantities and rectification effects.

Findings

Identification of operating points with maximum efficiency and power.

Discovery of interaction-induced resonances affecting thermoelectric performance.

Analysis of thermal rectification in open and closed circuit configurations.

Abstract

We investigate the thermoelectric transport properties of an interacting parallel double quantum dot in the Coulomb-blockade regime. Building on an analytical solution based on an equation-of-motion technique, we extend the formalism for the asymmetrically coupled situation and provide compact closed-form expressions for steady-state currents together with the differential conductance, Seebeck coefficient, and thermal conductance. We determine the operating points that maximize efficiency and output power of the system, clarifying their relation to standard near-equilibrium ZT expressions. We further study the thermal rectification in both the open- and closed-circuit configurations and derive an expression for the open-circuit case. Interaction-induced resonances are understood in terms of the poles of the resulting Green's function, generating gate and bias dependent regions of enhanced efficiency at finite power, negative differential thermal conductance, and finite thermal rectification.